Identification of materials



Paten ted Sept. 23, 194i Benjamin W. Collins, Swarthmore,

to American Viscose Cor Pa., assignor poration, Marcus Hook,

*Pa., a corporation of Delaware No Drawing.

4 Claims.

This invention relates to the manufacture of regenerated cellulose yarnsand other shapes containing a foreign substance, by means of which theymay be readily identified.

It is desirable to be able to identify the-origin and method ofmanufacture of regenerated'cellulose yarns and other shapes. This isoften not easy to do, however, for the ordinary means of identificationare not permanent and do not give positive results.

It is, therefore, an object of this invention to provide a method ofpositively identifying. the origin and method of manufacture ofregenerated cellulose yarns and other shapes.

Other objects and advantages of this invention will become apparent fromthe following description and appended claims.

Methods of identifying rayon yarns and other shapes have been suggestedin the United States Patent to Whitehead 1,885,878. However, the classof foreign substances mentioned in the Whitehead patent are not entirelysuitable for identification purposes in yarns or other shapes producedby regenerating cellulose from a cellulose solution. Such compounds asnickel and strontium chloride that are disclosed in the patent as beingtypical examples of identifying substances are readily soluble in water.By the same token they are readily leached out either during the copiousaqueous treatment required in the manufacture and finishing of allregenerated cellulose products or during the subsequent processes towhich such goods are commonly subjected, such as kier boiling, dyeing,sizing, soft finishing, and also ordinary laundering in the hands of theultimate consumer.

In contradistinction to this procedure, I have found that as a class,the most valuable identifying substances are those possessing thehighest degree of insolubility in water as well as in solutions ofacids, alkalies, desulphiding agents, bleaching agents, soaps, oils, oroily emulsions as well as organic solvents such as may be used, forinstance, in dry cleaning establishments. Furthermore, I have found thatsubstances possessing such highly desirable characteristics may besuccessfully introduced into the cellulose solution from which thecellulose product is to be regenerated, in the form of exceedinglyfinely divided suspensions in which the diameter of the larger particlesis of the order of 0.45 micron (0.00045 mm.). In such states ofsubdivision or colloidal dispersion, the particles readily pass throughthe interstices of ordinary filtration media as well as through theapertures of the Application November 25, 1938, Serial No. 242,282

spinnerets. Furthermore, as a means of providing a permanently anduniformly distributed identifying material the insoluble particles offerthe added advantage of remaining firmly fixed in the yarn or shape. Theycannot be washed away or moved from their original positions as is truein the case of soluble compounds which exhibit definite tendencies tolocalize or concentrate in the lower portions of skeins or fabrics hungup to dry.

Having described the advantages of such highly insoluble materials, Inow cite severaltypical ex amples and will describe in greater detailmethods for their successful introduction into the viscose process. Imay employ, by way of illustration, insoluble substances comprisingcompounds of gold, copper, silver, lithium, barium, cadmium, beryllium,lanthanum, boron, tin, thorium, cerium, zirconium, bismuth, arsenic,antimony, tantalum, uranium, chromium, molybdenum, tungsten, cobalt,praseodymium, and neodymium; such as the silicates of these metals, theoxides of beryllium, zirconium, bismuth, tantalum, chromium, molybdenumand tungsten; such organic derivatives as the oleates, stearates andlaurates of copper, silver, barium, cadmium, beryllium, tin, zirconium,bismuth, chromium, and cobalt; and various glasses to which these metalsor compounds thereof have been added. I may also employ the naturallyoccurring mineral ores such as spodumene, which is a double silicate ofaluminum and lithium; tourmaline, which is usually a combination oflithium, sodium, potassium, iron, magnesium, and manganese silicates;cerite, which contains silicates of cerium and allied materials;gadolinite, which usually contains silicates of iron, beryllium,yttrium, cerium, and erbium; and monazite, which usually containssilicates, phosphates of certain rare elements such as cerium,neodymium, praseodymium, lanthanum, and thorium.

These substances may be used separately or several of them together.

Any sufficiently insoluble compound of any of these or similar metallicbases may be reduced in ordinary pebble mills to the approximateparticle size mentioned above. The suspension in proper amounts then maybe added at any convenient stage in the viscose process prior to thespinning operation, providing, of course, that the particles aresubjected to thorough mechanical mixing to distribute them uniformlythroughout the cellulose solution.

I prefer to add the very smallest amount of the substance compatiblewith positive identilion parts of the yarn or shape in order to efiect.

general appear- 1 a perceptible change in their ance.

Obviously the laboratory procedures for ef- I fecting the identificationof celluloseaproducts produced in this manner will vary according. to

whichever may be the most sensitive characteristic reaction of thesubstancein question; The.

used may be proporof the identificationamounts of the substance tionedto the sensitiveness procedure, whether it be a delicate color reaction,a characteristic precipitate or-the result of a'spectographic analysis.v While I find that the above examples give the most desirable results,I do not wish to be limj ited to only these, for my invention covers theuse of other insoluble compounds asw ll. Also although the invention hasbeen described in connection with the viscose process, .it is to beunderstoodthat the invention is applicable to otherprocesses ofregenerating cellulose from a cellulose solution and. is intendedtocover yarns, threads, filaments, staple fibers, films, coatings, andother shapes'of regenerated cellulose.

Having thus described my invention, what I claim is:

1. A cellulosic spinning solution for the production of cellulosicshapes containing, in an amount insufficient to change the perceptiblegeneral characteristics of the shape, of the order of less than 1200parts per million parts of the shape, a material by which the shape maybe identified comprising an oxide of a member selected from the groupconsisting of beryllium, Zirconium, bismuth, tantalum, chromium,molybdenum and tungsten.

2, A cellulosic spinning solution for the pro- 5 duction of cellulosicshapes containing, in an amount insufiicient to change the perceptiblegeneral characteristics of the shape, of the order 'of less than 1200parts per million parts of the shape, a material by which the shape maybe identified comprising beryllium oxide.

3. A cellulosic spinning solution for the production of cellulosicshapes containing, in an amount insufficient to change the perceptiblegeneral characteristics of the shape, of the order of less than 1200parts per million parts of the shape, a material by which the shape maybe identified comprising zirconium oxide.

4. A cellulosic spinning solution for the proe duction of cellulosicshapes containing, in an amount insufficient to change the perceptiblegeneral characteristics of the shape, of the order of less than 1200parts per million parts of the shape, a material by which the shape maybe identified comprising molybdenum oxide.

BENJAMIN W. COLLINS.

